This project provides support for the participation of the Radiation Oncology Division of the University of Puerto Rico in the Radiation Therapy Oncology Group. This organization is constituted by a national group of academic institutions involved in prospective clinical research in radiation therapy of cancer. The University of Puerto Rico began its participation in the Radiation Therapy Oncology Group early in 1972. Study cases are contributed by the University Hospital, the San Juan City Hospital, and the Radiotherapy Institute of the Metropolitan Hospital, all of which form part of academic radiation therapy program. An additional institution, the San Juan Oncologic Hospital, may begin accessing cases during F.Y. 1981. This program contributes: case registration in RTOG registries, case accession for groupwide protocols, pilot Phase II study cases, protocol development, committee participation, and scienific publications.